Seat recliner

ABSTRACT

THIS INVENTION RELATES TO A SEAT RECLINER FOR CONTROLLING AN ANGLE OF RECLINATION OF A BACK-REST OF A SEAT, WHICH IS CHARACTERIZED, AMONG OTHERS, BY THE FACTS THAT NO CONTROLLING SPRING IS USED AS IN THE CONVENTIONAL DEVICES, AND THAT A SHOCK ABSORBER IS INCORPORATED SO AS TO PREVENT PROPAGATION OF VIBRATIONS PRODUCED IN THE CHASSIS FLOOR TO THE BACK-REST, AND IN WHICH AN INTERNAL GEAR IS CARRIED ON A BASE ARM FIXED TO A SEAT AND SEVERAL ROUND HOLES ARE FORMED IN A BACK ARM FIXED TO THE BACK-REST, WITH A RESILIENT PACKING BEING ROTATABLY FITTED INTO EACH OF SAID HOLES, AND AN EXTERNAL GEAR WITH TEETH LESS IN NUMBER THAN SAID INTERNAL GEAR IS COUPLED TO AND SUPPORTED BY SAID RESILIENT PACKINGS THROUGH SWINGABLE PINS. SAID EXTERNAL GEAR IS MESHED WITH SAID INTERNAL GEAR, AND IN THE CENTER HOLE OF SAID EXTERNAL GEAR IS FITTED A CAM PROVIDED ON A CAM SHAFT, THE LATTER CARRYING AT ITS END A GRIP. IN ACCORDANCE WITH ROTATION OF SAID GRIP, THE EXTERNAL GEAR IS ALSO ROTATED IN MESHED RELATION WITH THE INTERNAL GEAR THROUGH THE CAM, AND IN RESPONSE TO THIS ROTATING MOTION OF THE EXTERNAL GEAR, SAID SWINGABLE PINS ARE SWUNG ALONG A CONSTANT LOCUS WITHIN THE RESPECTIVE ROUND HOLES THROUGH THE RESILIENT PACKINGS TO THEREBY TRANSMIT THE MOVEMENT OF SAID EXTERNAL GEAR TO THE BACK ARM, SO AS TO IMPART AN INCLINATION TO THE BACK ARM CORRESPONDING TO THE GEAR RATIO BETWEEN THE INTERNAL GEAR AND THE EXTERNAL GEAR.

June 6, 1972 HIDEAKI YASUI ETA!- 3,667,804

I SEAT RECLINER Filed May 2'7, 1970 2 Sheets-Sheet 1 INVENTORS M "WMJune 6, 1972 HIDEAKI'YASUI ETAL 3,667,804

SEAT RECLINER Filed May 27, 1970 3 Sheets-Sheet ,3

HIDE A NTORS K! Y w S UKEO TSURU HTTORNEYS United States Patent O3,667,804 SEAT RECLINER Hideaki Yasui, 2-6-12 Nishi-rokugoo, Ota-ku,Tokyo, Japan, and Sukeo Tsurumi, 62-574 Niina, Mino, Osaka-fu, JapanFiled May 27, 1970, Ser. No. 40,871 Claims priority, application Japan,June 25 ,1969, 44/59,553 Int. Cl. A47c 1/024 US. Cl. 297-362 1 ClaimABSTRACT OF THE DISCLOSURE This invention relates to a seat recliner forcontrolling an angle of reclination of a back-rest of a seat, which ischaracterized, among others, by the facts that no controlling spring isused as in the conventional devices, and that a shock absorber isincorporated so as to prevent propagation of vibrations produced in thechassis floor to the back-rest, and in which an internal gear is carriedon a base arm fixed to a seat and several round holes are formed in aback arm fixed to the back-rest, with a resilient packing beingrotatably fitted into each of said holes, and an external gear withteeth less in number than said internal gear is coupled to and supportedby said resilient packings through swingable pins. Said external gear ismeshed with said internal gear, and in the center hole of said externalgear is fitted a cam provided on a cam shaft, the latter carrying at itsend a grip. In accordance with rotation of said grip, the external gearis also rotated in meshed relation with the internal gear through thecam, and in response to this rotating motion of the external gear, saidswingable pins are swung along a constant locus within the respectiveround holes through the resilient packings to thereby transmit themovement of said external gear to the back arm, so as to impart aninclination to the back arm corresponding to the gear ratio between theinternal gear and the external gear.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view of a seatrecliner of the present invention showing a grip side; FIG. 2 is aperspective view of the seat recliner in an exploded manner to show thecomponent parts of its construction; FIG. 3 is a side view similar toFIG. 1, but the grip portion being taken away from a cam shaft; FIG. 4is a perspective view of external thread gear-swinging means consistingof a swingable pin shaft of the external thread gear, its locus hole anda resilient packing material; and FIG. 5 is a perspective view of thegrip portion as seen from its back side.

DETAILED DESCRIPTION OF THE INVENTION This invention relates toimprovements in a seat recliner for controlling an angle of reclinationin a desired position of a seat in automobiles, railway vehicles and thelike.

The seat recliner of the known type generally has teeth on its back armsthreaded in three or four steps in predetermined angles, pawls engagingwith said teeth at an operative lever end, in which a back-rest of theseat is urged to have a normal angle by spring. Accordingly, the seatrecliner of the conventional structure provides the control of an angleof reclination afforded through operation of the lever for release of apawl from engage ment with the teeth on the back arm, with the back-restbeing inclined contrary to the urging force of spring, by engagement ofthe pawl to teeth threaded in several steps at angles as predetermined,whereby the back-rest of the reclining seat can be set up at an inclinedposition. In the conventional type of the seat recliner as described,

the drawbacks have been encountered as follows. The back-rest should beapplied a force in the direction of inclination resisting to the forceof spring which acts to return the back-rest always to its normalangular position. The back-rest also cannot be inclined at a position ofsmall angle between pitches of teeth except in fixed angles as providedby the number of teeth meshing with the pawl of the lever. Usually thelever can recover the back-rest from an inclined position to normalposition by releasing the pawl out of the teeth. Then the back rest israpidlybrought into its normal position by the action the spring,resulting in the shock and impulsive sounds producing quiteuncomfortableness. The differential gearing of the internal and externalgears in the prior art has also a drawback of causing vibration when theback-rest is adjusted of its angle.

The present invention provides a seat recliner which affordsimprovements over such conventional devices.

A feature of the present invention resides in the provision of a seatrecliner in use of a grip instead of a spring for the recovery of theback-rest from an inclined position to its normal position, which gripis adapted to resolve so as incline or restore the back-rest to theinitial position with a quiet, swift, and very pleasant movement.

Other feature of the invention is to provide a seat recliner whichpermits very fine control of the back-rest. Here, the back-rest can beset up in position at a preferred angle of inclination by rotaryoperation of the grip.

Still other feature of the invention is to provide a seat recliner inwhich the back-rest can be controlled free from vibration and theresonance transmitted to the backrest from the vehicle floor can well bedamped to retain a pleasant seat condition.

According to the invention having such features as described, theconstruction of the device will now be described. 7

There is provided a base arm fixed to a seat in the vehicle. The arm hasan internal gear. An external gear is provided at a back arm fixed tothe back-rest through a swinging pins. The external gear has teeth lessin number than the internal gear. Said external gearis in mesh with saidinternal gear. In the center hole of the external gear is fitted a camprovided on a cam shaft. By rotation of the grip attached at the end ofthe cam shaft the rotary movement of the external gear meshing with theinternal gear is transmitted to the back arm through the swinging pinsso as to impart an inclination to the back arm corresponding to theratio of threaded teeth of the internal gear and the external gear.

The swinging pins connect the external gear to th back arm through aresilient packing fitted into a round hole provided in the back arm.Said swinging pins are provided to swing along a constant locus withinthe round hole corresponding to the swing movement of the external gearthrough the cam.

Particulars of the seat recliner according to the invention will now bedescribed with reference to the accompanying drawings.

In the drawings, reference numeral 1 denotes a base arm fixed at theseat side. The base arm is provided with an internal gear 2, having atthe center thereof a support hole 3 for a cam shaft. Numeral 4designates a back arm fixed to a back-rest, which is also provided witha support hole 5 to journal the cam shaft. There are provided threeround holes 6a, 6b, 6c spaced at equal intervals along a circumferentiallocus around the Support hole 5. These holes are fitted with resilientpackings 17a, 17b, made of, for example, rubber, synthetic resin or thelike. Numeral 13 designates an external gear which is formed with teethless in number than those of the internal gear 2.

At the thrust surface of the external gear 13 against the back-rest 4are provided three swinging pins 15a, 15b,"15c

p with equal angular distances. These are located eccentrically relativeto the round" holes 6a, 6b, 60 provided on the back-rest. The swingingpins 15a, 15b, 15c are fitted to small holes 19a, 19b, 19c eccentricallyprovided of the resilient packings fitted to the above-described roundholes 6a, 6b, 6c and the external gear 13 is attached to the back arm 4.

Numeral 11 denotes a cam which is integrally formed on a cam shaft '9 or10 provided eccentrically therewith. The cam 11 is loosely and rotatablyfitted to a center hole 14 of the external gear 13. On side 9 of the camshaft is loosely carried in the support hole 3 provided on the base arm1, the end of which is caulked with a ring washer 16 fitted thereto.Another side 10 of the cam shaft is loosely carried in a support holeprovided at the back arm 4. The external gear 13 is rotated with aportion of teeth meshed with the internal gear 2 by the above-mentionedcam 11. The rotation of the external gear 13 is carried out in theamount of eccentric displacement of the cam 11 produced in the course inwhich the serration 12 at the end of the cam shaft is operatinglyconnected to a central serration cylinder 20 of a grip 7 and the camshaft 9 or 10 is rotated by rotation of the grip 7. The grip 7 has aroller tip 8 at an eccentric position. The roller tip can be held torotate the grip 7 if a rapid control is necessitated so as to obtain aswift and light operation.

In operation, the grip 7 may be rotated. Then the external gear 13through the cam shaft 9 or 10 and cam 11 makes swing movement and,meshing with the internal gear 2, rotates. With the rotation of theexternal gear 13 the resilient packings 17a, 17b, 17c fitted into roundholes 6a, 6b, 6c of the back arm 4 rotate with the swinging pins 15a,15b, 150 in the round holes 6a, 6b, 6c and impart an inclination angleto the back arm 4. For instance, assume that the number of teeth of theexternal gear 3 is A and the number of teeth of the internal gear 2 B,then the inclination angle of the external gear 13 relative to theinternal gear 2 may be expressed by the rotation for one rotation of thegrip 7. Normally in ordinary differential gear mechanisms, thedifference in the number of teeth of the internal and external gears isgiven in one tooth to obtain the higher yield strength against thetorque and, consequently, the control speed of operation is too small soas to make difficult to adjust the back-rest through a large angle veryspeedily.

In accordance with the present invention, the eccentric wedge action ofthe resilient packings 17a, 17b, 17c may be most effectively used withlarge difference in the number of teeth between the external gear 13 andthe internal gear 2, wherein for instance the number of teeth of theexternal gear 13 may be 30 teeth and the number of teeth of the internalgear 2 26 teeth, the difference of the teeth thus being 4 in the number.As a result, the angle of the back arm 4 with the base arm 1 in onerotation of the grip 7 can be displaced through about 56. There may beobtained a stable control in the forward and rearward directions as wellas time control as desired. The external force from the back-rest can beset oft by the eccentric wedge action of the packings 17a, 17b, withoutmovement of the back rest but surely in locked condition at a fixedposition.

With the simple construction as heretofore described, the seat reclinerof the invention provides a rapid and sure control of the inclinationangle of the back-rest through rotation of the grip at a preferred anglein an infinite manner. The resilient packings serve to dampen thevibration and secure quiet and smooth control of the inclination angleconsequent on a cheap and practical seat recliner.

We claim:

1. A seat back-rest recliner comprising a base arm connected to theseat, a back arm connected to the back-rest, said base arm beingprovided with an internal gear and a central opening, said back armbeing provided with a plurality of round holes arranged on acircumferential locus around a supporting hole, resilient packings eachbeing positioned in one of said round holes, an external gear meshingwith said internal gear, but having a different number of teeth thansaid internal gear and having a central opening, pins projecting fromsaid external gear and fitting eccentrically in said resilient packings,a cam shaft rotatably supported through said base arm central openingand said back arm supporting hole, a cam fixedly mounted on said camshaft and rotatably positioned in said external gear central opening,means for rotating said cam shaft whereby said cam shaft can be rotatedcausing said external gear to swingingly rotate relative to saidinternal gear by the amount of eccentric displacement of said cam andsaid swinging rotation being transmitted to said back arm through saidswinging pins so as to impart an inclination to said back arm by thedifference in the number of teeth of said internal gear and saidexternal gear.

References Cited UNITED STATES PATENTS 3,423,785 1/ 1969 Pickles 297-379X 3,359,685 12/1967 Hodgen 16140 3,401,979 9/ 1968 Putsch 297-3623,432,881 3/ 1969 Putsch 297-3 66 3,479,088 11/ 1969 Bonnaud 297-3 62 XFRANCIS K. ZUGEL, Primary Examiner US. Cl. X.R. 297366

